Without limiting the scope of the disclosure, this background section is described in connection with external fixation devices and specifically connection rods. Generally, external fixation devices are commonly used in a variety of surgical procedures including limb lengthening, deformity correction, fracture reduction and treatment of non-unions, mal-unions and bone defects. The process involves a rigid framework comprising one or more rings that are placed externally around the limb and attached to bone segments using wires and half pins inserted into the bone segments and connected to the related section of the external rigid framework. The opposite rings of the rigid framework are interconnected by either threaded or telescopic rods directly or in conjunction with hinges or ball joints, which allow the surgeon to connect opposite rings that are not parallel to each other after manipulation with bone segments either rapidly (acutely) or gradually over a period of time.
For example, in bone fracture reduction or non-union treatment, the wires and half pins are inserted into each bone segment and attached to rings of a rigid framework. The rigid framework is used to acutely reduce a displacement and restore alignment between the bone segments. During the realignment of the bone segments, the orientations of opposite rings often are not parallel. Those opposite rings of the rigid framework are connected together by threaded and/or telescopic rods with attached hinges or ball joints. This allows the opposite bone segment to be rigidly fixed until complete fracture healing or bone consolidation is completed.
The hinges or ball joints may have a male or female connection mechanism in order to facilitate coupling of the threaded or telescopic rods to the fixation rings. For example, a male connection mechanism may have a protruding connection element, e.g., short threaded rod or socket, for insertion into a receiving portion of a fixation ring. On the other hand, a female connection mechanism may receive a connection element, e.g., screw or bolt, from a fixation ring.